Usually, the arrangement of the shelves on a piece of refrigeration appliances is predefined at the factory, that is, the usability of the refrigerator is limited by a previously established configuration by the manufacturer. In many domestic refrigerators and/or freezers, only the removal of shelves is permitted in order to allow the placement of foods or items of larger dimensions.
The said limitation prevents the optimization of the internal space of the said cabinet, in such a manner that the user is prevented from placing a desired quantity of items in the refrigerator or he is forced to put them in a disorganized manner often stacked randomly.
Keeping in view the abovementioned problems, various mechanisms have been developed so as to allow the moving/placing of shelves inside the refrigerator's cabinet in such a manner as to provide greater flexibility and usability.
For example, the North American document US 2004/0195945 relates to a refrigerator that has one shelf which may be associated to the internal walls of its cabinet by means of a supporting arm in a “Z” shape and which is able to move in a rotational manner, pivoting around an axis. The said supporting arm comprises a first pin mounted in an articulated manner into a hole that is positioned parallel to a second pin fitted to the shelf, wherein both pins are interlinked by an intermediate section. In its rotating movement of the supporting arm, the pins remain parallel to each other, whilst the intermediate section tilts, moving in angular manner. Although the concept of a configuration that provides vertical displacement of a shelf without tilting it is shown in this document, the need for making holes inside the cabinet represents a disadvantage, as it is necessary to make a permanent change to the internal structure of the cabinet, which requires a new specific project for this application. Besides, the supporting structure of the configuration described in this document is, apparently, not robust and resistant at all, since all the weight of the shelves as well as the items placed on it is only supported by the pins. In this way, if any mechanical stresses are applied on the structure the said pins may break, causing the shelf to fall.
The Japanese document JP 2003176977 describes a refrigerator shelf supported by a mobile structure in an “X” shape. Both arms of this structure are able to move angularly in opposite directions, so as to raise or lower the shelf that is supported at the upper ends of the said arms. The arms also comprise pins that fit into holes within the refrigerator's cabinet, thus allowing the shelves to be associated to the cabinet through its movable “X” structure. Again, besides the fact that this Japanese document shows a configuration that provides vertical displacement of a shelf without it tilting, there is still the need to make holes inside the refrigerator's cabinet. Additionally, this “X” structure configuration as described in this state of the art document is supported only by the pins, which makes it weak and with little resistance when applying greater mechanical stresses to the shelf.
The North American document U.S. Pat. No. 4,528,825 describes a movable shelf that may be moved angularly and stabilized at two vertical positions inside the refrigerator's cabinet. This movement is allowed by means of bars mounted on the movable shelf and onto a support, which on its turn is associated to a fixed upper shelf. Although this document shows a configuration that provides vertical displacement of a shelf without causing it to tilt, when the movable shelf is at the top position, it is not possible to place any item or food on it, due to the hindrance caused by the presence of the top shelf. In this way, the movable shelf may be used without the need to tilt it, but only in its bottom position, representing a usability disadvantage.
International document WO 2006/122913 relates to a shelf that is able to be stabilized at two positions: top and bottom, by means of a structure made up of two supporting elements installed on the internal side walls of the refrigerator's cabinet. The shelf has a first and second movable section that is movable between each other. The first section is also movable in relation to the supporting elements by means of pins. The second section comprises sliders that slide over guides that are comprised by the support elements. Due to the construction arrangement of the unit formed by the shelf and by the supporting elements, an tilting of the shelf occurs when it is being moved from its bottom position to the top position, which may cause items placed on it to fall. Besides, the mechanism described in this document apparently presents a constructive complexity and consequently, it is difficult to manufacture and implement it, adding a higher final cost.
Finally, the document WO 2005/001352 describes a movable shelf that may be moved from a bottom position to an upper position by means of internal guides of side supports installed inside the refrigeration cabinet. The constructive configuration shown in this document also allows the shelf to be tilted when it is being moved from a bottom to an upper position or vice-versa.
Therefore, there is still no known satisfactory and efficient solution that allows the optimization of internal space of the cabinet of a refrigeration appliance, and which presents low cost, reliability, performance and usability.